CAG Information Retention in User Equipment Non-Volatile Memory
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Solution Overview
Problem
In wireless communications, particularly in LTE and 5G systems, user equipment (UE) loses closed access group (CAG) information when switched off, requiring network re-provisioning upon restart, which disrupts network access and selection processes.
Innovation Solution
Storing CAG information in non-volatile memory within the UE or USIM, allowing the UE to retain and use this information for network selection even after power cycles, and managing CAG-only indications to enable or restrict access to specific cells based on available identifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If CAG information is stored in volatile memory, then the UE can operate during power-on state, but the CAG information is lost when the UE is switched off
Solution Approach 1:
The patent applies preliminary action by proactively storing CAG information in non-volatile memory before the UE is switched off. The network configures the UE with CAG information lists that include CAG identifiers, PLMN identifiers, and access restriction parameters, which are then persistently stored. This ensures the information is readily available upon power-up without requiring re-provisioning, thus preventing information loss while maintaining manageable complexity through automated network-side configuration.
2Loss of time
If the UE re-provisions CAG information from network upon restart, then information freshness is maintained, but network access process is disrupted and time is lost
Solution Approach 1:
The patent implements preliminary action by having the network configure and the UE store CAG information lists in non-volatile memory before power-off occurs. This pre-stored information enables immediate network access upon restart without requiring time-consuming re-provisioning procedures. The UE can directly use the stored CAG identifiers and access parameters to camp on appropriate cells, significantly reducing access time while maintaining reliable network connection through validated configuration data.
3Reliability
If CAG only indication is set to restrict access, then authorized access control is improved, but access flexibility is reduced when CAG identifiers are absent
Solution Approach 1:
The patent applies dynamics by making the CAG only indication configurable and conditional rather than fixed. The network can dynamically set the CAG only indication based on the UE's subscription profile and service requirements. When CAG identifiers are present in the stored information, the UE enforces restricted CAG-only access for high reliability. When CAG identifiers are absent or expired, the UE can dynamically switch to allow access to normal cells, providing adaptability. This dynamic behavior ensures both reliable access control when needed and flexible fallback capability when CAG information is unavailable.
Data Source
AI summary
Aspects of the disclosure provide methods and an apparatus for enhancement of closed access groups (CAGs). For example, the apparatus can include a non-volatile memory, receiving circuitry, transmitting circuitry and processing circuitry. The receiving circuitry can be configured to receive a configuration update command message and a registration accept message, each of which includes a CAG information list IE containing a CAG information list. The transmitting circuitry can be configured to transmit a configuration update complete message and a registration request message. The processing circuitry can be configured to store the CAG information list of the CAG information list IE in the non-volatile memory, and select a public land mobile network based on the CAG information list stored in the non-volatile memory.